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Parisi K, McKenna JA, Lowe R, Harris KS, Shafee T, Guarino R, Lee E, van der Weerden NL, Bleackley MR, Anderson MA. Hyperpolarisation of Mitochondrial Membranes Is a Critical Component of the Antifungal Mechanism of the Plant Defensin, Ppdef1. J Fungi (Basel) 2024; 10:54. [PMID: 38248963 PMCID: PMC10817573 DOI: 10.3390/jof10010054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 12/30/2023] [Accepted: 01/03/2024] [Indexed: 01/23/2024] Open
Abstract
Plant defensins are a large family of small cationic proteins with diverse functions and mechanisms of action, most of which assert antifungal activity against a broad spectrum of fungi. The partial mechanism of action has been resolved for a small number of members of plant defensins, and studies have revealed that many act by more than one mechanism. The plant defensin Ppdef1 has a unique sequence and long loop 5 with fungicidal activity against a range of human fungal pathogens, but little is known about its mechanism of action. We screened the S. cerevisiae non-essential gene deletion library and identified the involvement of the mitochondria in the mechanism of action of Ppdef1. Further analysis revealed that the hyperpolarisation of the mitochondrial membrane potential (MMP) activates ROS production, vacuolar fusion and cell death and is an important step in the mechanism of action of Ppdef1, and it is likely that a similar mechanism acts in Trichophyton rubrum.
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Affiliation(s)
- Kathy Parisi
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Australia
- Hexima Ltd., Preston 3072, Australia
| | - James A. McKenna
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Australia
- Hexima Ltd., Preston 3072, Australia
| | - Rohan Lowe
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Australia
- Hexima Ltd., Preston 3072, Australia
| | - Karen S. Harris
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Australia
- Hexima Ltd., Preston 3072, Australia
| | - Thomas Shafee
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Australia
| | - Rosemary Guarino
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Australia
- Hexima Ltd., Preston 3072, Australia
| | - Eunice Lee
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Australia
- Hexima Ltd., Preston 3072, Australia
| | - Nicole L. van der Weerden
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Australia
- Hexima Ltd., Preston 3072, Australia
| | - Mark R. Bleackley
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Australia
- Hexima Ltd., Preston 3072, Australia
| | - Marilyn A. Anderson
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Australia
- Hexima Ltd., Preston 3072, Australia
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Pirc Marolt T, Kramar B, Vovk A, Podgornik H, Šuput D, Milisav I. Therapeutic Dosage of Antipsychotic Drug Aripiprazole Induces Persistent Mitochondrial Hyperpolarisation, Moderate Oxidative Stress in Liver Cells, and Haemolysis. Antioxidants (Basel) 2023; 12:1930. [PMID: 38001783 PMCID: PMC10669280 DOI: 10.3390/antiox12111930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 10/16/2023] [Accepted: 10/23/2023] [Indexed: 11/26/2023] Open
Abstract
Aripiprazole has fewer metabolic side effects than other antipsychotics; however, there are some severe ones in the liver, leading to drug-induced liver injury. Repeated treatment with aripiprazole affects cell division. Since this process requires a lot of energy, we decided to investigate the impact of aripiprazole on rat liver cells and mitochondria as the main source of cellular energy production by measuring the mitochondrial membrane potential, respiration, adenosine triphosphate (ATP) production, oxidative stress, antioxidative response, and human blood haemolysis. Here, we report that mitochondrial hyperpolarisation from aripiprazole treatment is accompanied by higher reactive oxygen species (ROS) production and increased antioxidative response. Lower mitochondrial and increased glycolytic ATP synthesis demand more glucose through glycolysis for equal ATP production and may change the partition between the glycolysis and pentose phosphate pathway in the liver. The uniform low amounts of the haemolysis of erythrocytes in the presence of aripiprazole in 25 individuals indicate lower quantities of the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH+H+), which is in accordance with a decreased activity of glucose 6-phosphate dehydrogenase and the lower dehydrogenase activity upon aripiprazole treatment. The lower activity of glucose 6-phosphate dehydrogenase supports a shift to glycolysis, thus rescuing the decreased mitochondrial ATP synthesis. The putative reduction in NADPH+H+ did not seem to affect the oxidised-to-reduced glutathione ratio, as it remained equal to that in the untreated cells. The effect of aripiprazole on glutathione reduction is likely through direct binding, thus reducing its total amount. As a consequence, the low haemolysis of human erythrocytes was observed. Aripiprazole causes moderate perturbations in metabolism, possibly with one defect rescuing the other. The result of the increased antioxidant enzyme activity upon treatment with aripiprazole is increased resilience to oxidative stress, which makes it an effective drug for schizophrenia in which oxidative stress is constantly present because of disease and treatment.
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Affiliation(s)
- Tinkara Pirc Marolt
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloska 4, 1000 Ljubljana, Slovenia
| | - Barbara Kramar
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloska 4, 1000 Ljubljana, Slovenia
| | - Andrej Vovk
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloska 4, 1000 Ljubljana, Slovenia
| | - Helena Podgornik
- Department of Haematology, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia
- Faculty of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, 1000 Ljubljana, Slovenia
| | - Dušan Šuput
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloska 4, 1000 Ljubljana, Slovenia
| | - Irina Milisav
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloska 4, 1000 Ljubljana, Slovenia
- Laboratory of Oxidative Stress Research, Faculty of Health Sciences, University of Ljubljana, Zdravstvena pot 5, 1000 Ljubljana, Slovenia
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Tickner BJ, Platas-Iglesias C, Duckett SB, Angelovski G. In Situ Ternary Adduct Formation of Yttrium Polyaminocarboxylates Leads to Small Molecule Capture and Activation. Chemistry 2022; 28:e202201780. [PMID: 35853826 DOI: 10.1002/chem.202201780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Indexed: 01/07/2023]
Abstract
In this work the chemistry of yttrium complexes is exploited for small molecule capture and activation. Nuclear magnetic resonance (NMR) and density functional theory (DFT) studies were used to investigate the in situ formation of solution state ternary yttrium-acetate, yttrium-bicarbonate, and yttrium-pyruvate adducts with a range of polyaminocarboxylate chelates. These studies reveal that [Y(DO3A)(H2 O)2 ] (H3 DO3A - 1,4,7,10-tetraazacyclododecane-1,4,7-tricarboxylic acid) and [Y(EDTA)(H2 O)q ]- (H4 EDTA - ethylenediaminetetraacetic acid, q = 2 and 3) are able to form ternary adducts with bicarbonate and pyruvate. In the latter, unusual decarboxylation of pyruvate to form acetic acid and CO2 was observed and further studied using SABRE-hyperpolarised 13 C NMR (SABRE - signal amplification by reversible exchange) to provide information about the reaction timescale and lifetime of intermediates involved in this conversion. The work presented demonstrates that yttrium complexes can capture and activate small molecules, which may lead to novel and useful applications of this metal in catalysis and medical imaging.
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Affiliation(s)
- Ben J Tickner
- Centre for Hyperpolarisation in Magnetic Resonance, Department of Chemistry, University of York, Heslington, YO10 5NY, United Kingdom.,MR Neuroimaging agents, Max Planck Institute for Biological Cybernetics, Tübingen, 72076, Germany
| | - Carlos Platas-Iglesias
- Centro de Investigacións Científicas Avanzadas (CICA), Departamento de Química, Facultade de Ciencias, Universidade da Coruña, A Coruña, 15001, Spain
| | - Simon B Duckett
- Centre for Hyperpolarisation in Magnetic Resonance, Department of Chemistry, University of York, Heslington, YO10 5NY, United Kingdom
| | - Goran Angelovski
- MR Neuroimaging agents, Max Planck Institute for Biological Cybernetics, Tübingen, 72076, Germany.,Laboratory of Molecular and Cellular Neuroimaging, International Center for Primate Brain Research (ICPBR), Center for Excellence in Brain Science and Intelligence Technology (CEBSIT), Chinese Academy of Sciences (CAS), Shanghai, 200031, PR China
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Robertson TBR, Clarke LJ, Mewis RE. Rapid SABRE Catalyst Scavenging Using Functionalized Silicas. Molecules 2022; 27:332. [PMID: 35056646 DOI: 10.3390/molecules27020332] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 12/16/2021] [Accepted: 12/21/2021] [Indexed: 02/07/2023]
Abstract
In recent years the NMR hyperpolarisation method signal amplification by reversible exchange (SABRE) has been applied to multiple substrates of potential interest for in vivo investigation. Unfortunately, SABRE commonly requires an iridium-containing catalyst that is unsuitable for biomedical applications. This report utilizes inductively coupled plasma-optical emission spectroscopy (ICP-OES) to investigate the potential use of metal scavengers to remove the iridium catalytic species from the solution. The most sensitive iridium emission line at 224.268 nm was used in the analysis. We report the effects of varying functionality, chain length, and scavenger support identity on iridium scavenging efficiency. The impact of varying the quantity of scavenger utilized is reported for the three scavengers with the highest iridium removed from initial investigations: 3-aminopropyl (S1), 3-(imidazole-1-yl)propyl (S4), and 2-(2-pyridyl) (S5) functionalized silica gels. Exposure of an activated SABRE sample (1.6 mg mL-1 of iridium catalyst) to 10 mg of the most promising scavenger (S5) resulted in <1 ppm of iridium being detectable by ICP-OES after 2 min of exposure. We propose that combining the approach described herein with other recently reported approaches, such as catalyst separated-SABRE (CASH-SABRE), would enable the rapid preparation of a biocompatible SABRE hyperpolarized bolus.
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Rayner PJ, Burns MJ, Fear EJ, Duckett SB. Steric and electronic effects on the 1 H hyperpolarisation of substituted pyridazines by signal amplification by reversible exchange. Magn Reson Chem 2021; 59:1187-1198. [PMID: 33729592 PMCID: PMC8650576 DOI: 10.1002/mrc.5152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 03/08/2021] [Accepted: 03/10/2021] [Indexed: 05/05/2023]
Abstract
Utility of the pyridazine motif is growing in popularity as pharmaceutical and agrochemical agents. The detection and structural characterisation of such materials is therefore imperative for the successful development of new products. Signal amplification by reversible exchange (SABRE) offers a route to dramatically improve the sensitivity of magnetic resonance methods, and we apply it here to the rapid and cost-effective hyperpolarisation of substituted pyridazines. The 33 substrates investigated cover a range of steric and electronic properties and their capacity to perform highly effective SABRE is assessed. We find the method to be tolerant to a broad range of electron donating and withdrawing groups; however, good sensitivity is evident when steric bulk is added to the 3- and 6-positions of the pyridazine ring. We optimise the method by reference to a disubstituted ester that yields signal gains of >9000-fold at 9.4 T (>28% spin polarisation).
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Affiliation(s)
- Peter J. Rayner
- Centre for Hyperpolarisation in Magnetic Resonance, Department of ChemistryUniversity of YorkYorkUK
| | - Michael J. Burns
- Centre for Hyperpolarisation in Magnetic Resonance, Department of ChemistryUniversity of YorkYorkUK
| | - Elizabeth J. Fear
- Centre for Hyperpolarisation in Magnetic Resonance, Department of ChemistryUniversity of YorkYorkUK
| | - Simon B. Duckett
- Centre for Hyperpolarisation in Magnetic Resonance, Department of ChemistryUniversity of YorkYorkUK
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Robertson TBR, Gilbert N, Sutcliffe OB, Mewis RE. Hyperpolarisation of Mirfentanil by SABRE in the Presence of Heroin. Chemphyschem 2021; 22:1059-1064. [PMID: 33871116 DOI: 10.1002/cphc.202100165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/05/2021] [Indexed: 11/06/2022]
Abstract
Mirfentanil, a fentanyl derivative that is a μ-opioid partial agonist, is hyperpolarised via Signal Amplification By Reversible Exchange (SABRE), a para-hydrogen-based technique. [Ir(IMes)(COD)Cl] (IMes=1,3-bis(2,4,6-trimethylphenyl)imidazole-2-ylidene, COD=cyclooctadiene) was employed as the polarisation transfer catalyst. Following polarisation transfer at 6.5 mT, the pyrazine-protons were enhanced by 78-fold (polarisation, P=0.04 %). The complex [Ir(IMes)(H)2 (mirfentanil)2 (MeOH)]+ is proposed to form based on the observation of two hydrides at δ -22.9 (trans to mirfentanil) and -24.7 (trans to methanol). In a mixture of mirfentanil and heroin, the former could be detected using SABRE at concentrations less than 1 % w/w. At the lowest concentration analyzed, the amount of mirfentanil present was 0.18 mg (812 μM) and produced a signal enhancement of -867-fold (P=0.42 %). following polarisation transfer at 6.5 mT.
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Affiliation(s)
- Thomas B R Robertson
- Department of Natural Sciences, Manchester Metropolitan University, John Dalton Building, Chester St., Manchester, M1 5GD, UK.,Current address: School of Chemistry, University of Southampton, SO17 1BJ, Southampton, UK
| | - Nicolas Gilbert
- Department of Natural Sciences, Manchester Metropolitan University, John Dalton Building, Chester St., Manchester, M1 5GD, UK.,MANchester DRug Analysis and Knowledge Exchange (MANDRAKE), Manchester Metropolitan University, John Dalton Building, Chester St., Manchester, M1 5GD, UK
| | - Oliver B Sutcliffe
- Department of Natural Sciences, Manchester Metropolitan University, John Dalton Building, Chester St., Manchester, M1 5GD, UK.,MANchester DRug Analysis and Knowledge Exchange (MANDRAKE), Manchester Metropolitan University, John Dalton Building, Chester St., Manchester, M1 5GD, UK
| | - Ryan E Mewis
- Department of Natural Sciences, Manchester Metropolitan University, John Dalton Building, Chester St., Manchester, M1 5GD, UK.,MANchester DRug Analysis and Knowledge Exchange (MANDRAKE), Manchester Metropolitan University, John Dalton Building, Chester St., Manchester, M1 5GD, UK
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Robertson TBR, Antonides LH, Gilbert N, Benjamin SL, Langley SK, Munro LJ, Sutcliffe OB, Mewis RE. Hyperpolarization of Pyridyl Fentalogues by Signal Amplification By Reversible Exchange (SABRE). ChemistryOpen 2019; 8:1375-1382. [PMID: 31844604 PMCID: PMC6892445 DOI: 10.1002/open.201900273] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 09/24/2019] [Indexed: 11/06/2022] Open
Abstract
Fentanyl, also known as 'jackpot', is a synthetic opiate that is 50-100 times more potent than morphine. Clandestine laboratories produce analogues of fentanyl, known as fentalogues to circumvent legislation regarding its production. Three pyridyl fentalogues were synthesized and then hyperpolarized by signal amplification by reversible exchange (SABRE) to appraise the forensic potential of the technique. A maximum enhancement of -168-fold at 1.4 T was recorded for the ortho pyridyl 1H nuclei. Studies of the activation parameters for the three fentalogues revealed that the ratio of ligand loss trans to hydride and hydride loss in the complex [Ir(IMes)(L)3(H)2]+ (IMes=1,3-bis(2,4,6-trimethylphenyl)imidazole-2-ylidene) ranged from 0.52 to 1.83. The fentalogue possessing the ratio closest to unity produced the largest enhancement subsequent to performing SABRE at earth's magnetic field. It was possible to hyperpolarize a pyridyl fentalogue selectively from a matrix that consisted largely of heroin (97 : 3 heroin:fentalogue) to validate the use of SABRE as a forensic tool.
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Affiliation(s)
- Thomas B. R. Robertson
- Department of Natural SciencesManchester Metropolitan University John Dalton Building, Chester St.Manchester, M1 5GDUK
| | - Lysbeth H. Antonides
- Department of Natural SciencesManchester Metropolitan University John Dalton Building, Chester St.Manchester, M1 5GDUK
- Leverhulme Research Centre for Forensic ScienceUniversity of DundeeDundeeDD1 5EHUK
| | - Nicolas Gilbert
- Department of Natural SciencesManchester Metropolitan University John Dalton Building, Chester St.Manchester, M1 5GDUK
- MANchester DRug Analysis and Knowledge Exchange (MANDRAKE)Manchester Metropolitan University John Dalton Building, Chester St.ManchesterM1 5GDUK
| | - Sophie L. Benjamin
- School of Science and TechnologyNottingham Trent UniversityNottinghamNG11 8NSUK
| | - Stuart K. Langley
- Department of Natural SciencesManchester Metropolitan University John Dalton Building, Chester St.Manchester, M1 5GDUK
| | - Lindsey J. Munro
- Department of Natural SciencesManchester Metropolitan University John Dalton Building, Chester St.Manchester, M1 5GDUK
| | - Oliver B. Sutcliffe
- Department of Natural SciencesManchester Metropolitan University John Dalton Building, Chester St.Manchester, M1 5GDUK
- MANchester DRug Analysis and Knowledge Exchange (MANDRAKE)Manchester Metropolitan University John Dalton Building, Chester St.ManchesterM1 5GDUK
| | - Ryan E. Mewis
- Department of Natural SciencesManchester Metropolitan University John Dalton Building, Chester St.Manchester, M1 5GDUK
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Richardson PM, Jackson S, Parrott AJ, Nordon A, Duckett SB, Halse ME. A simple hand-held magnet array for efficient and reproducible SABRE hyperpolarisation using manual sample shaking. Magn Reson Chem 2018; 56:641-650. [PMID: 29193324 PMCID: PMC6001426 DOI: 10.1002/mrc.4687] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 11/15/2017] [Accepted: 11/19/2017] [Indexed: 05/22/2023]
Abstract
Signal amplification by reversible exchange (SABRE) is a hyperpolarisation technique that catalytically transfers nuclear polarisation from parahydrogen, the singlet nuclear isomer of H2 , to a substrate in solution. The SABRE exchange reaction is carried out in a polarisation transfer field (PTF) of tens of gauss before transfer to a stronger magnetic field for nuclear magnetic resonance (NMR) detection. In the simplest implementation, polarisation transfer is achieved by shaking the sample in the stray field of a superconducting NMR magnet. Although convenient, this method suffers from limited reproducibility and cannot be used with NMR spectrometers that do not have appreciable stray fields, such as benchtop instruments. Here, we use a simple hand-held permanent magnet array to provide the necessary PTF during sample shaking. We find that the use of this array provides a 25% increase in SABRE enhancement over the stray field approach, while also providing improved reproducibility. Arrays with a range of PTFs were tested, and the PTF-dependent SABRE enhancements were found to be in excellent agreement with comparable experiments carried out using an automated flow system where an electromagnet is used to generate the PTF. We anticipate that this approach will improve the efficiency and reproducibility of SABRE experiments carried out using manual shaking and will be particularly useful for benchtop NMR, where a suitable stray field is not readily accessible. The ability to construct arrays with a range of PTFs will also enable the rapid optimisation of SABRE enhancement as function of PTF for new substrate and catalyst systems.
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Affiliation(s)
- Peter M. Richardson
- Centre for Hyperpolarisation in Magnetic Resonance (CHyM), Department of ChemistryUniversity of YorkYorkUK
| | - Scott Jackson
- Centre for Hyperpolarisation in Magnetic Resonance (CHyM), Department of ChemistryUniversity of YorkYorkUK
| | - Andrew J. Parrott
- WestCHEM, Department of Pure and Applied Chemistry and CPACTUniversity of StrathclydeGlasgowUK
| | - Alison Nordon
- WestCHEM, Department of Pure and Applied Chemistry and CPACTUniversity of StrathclydeGlasgowUK
| | - Simon B. Duckett
- Centre for Hyperpolarisation in Magnetic Resonance (CHyM), Department of ChemistryUniversity of YorkYorkUK
| | - Meghan E. Halse
- Centre for Hyperpolarisation in Magnetic Resonance (CHyM), Department of ChemistryUniversity of YorkYorkUK
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Norcott P, Burns MJ, Rayner PJ, Mewis RE, Duckett SB. Using 2 H labelling to improve the NMR detectability of pyridine and its derivatives by SABRE. Magn Reson Chem 2018; 56:663-671. [PMID: 29274294 PMCID: PMC6001449 DOI: 10.1002/mrc.4703] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 12/07/2017] [Accepted: 12/10/2017] [Indexed: 05/08/2023]
Abstract
By introducing a range of 2 H labels into pyridine and the para-substituted agents, methyl isonicotinate and isonicotinamide, we significantly improve their NMR detectability in conjunction with the signal amplification by reversible exchange process. We describe how the rates of T1 relaxation for the remaining 1 H nuclei are increased and show how this leads to a concomitant increase in the level of 1 H and 13 C hyperpolarization that can ultimately be detected.
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Affiliation(s)
| | | | | | - Ryan E. Mewis
- Department of ChemistryUniversity of YorkYorkYO10 5DDUK
- Division of Chemistry and Environmental ScienceManchester Metropolitan UniversityManchesterGreater ManchesterUK
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Fujii N, Louie JC, McNeely BD, Amano T, Nishiyasu T, Kenny GP. Mechanisms of nicotine-induced cutaneous vasodilation and sweating in young adults: roles for K Ca, K ATP, and K V channels, nitric oxide, and prostanoids. Appl Physiol Nutr Metab 2017; 42:470-478. [PMID: 28177721 DOI: 10.1139/apnm-2016-0615] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We evaluated the influence of K+ channels (i.e., Ca2+-activated K+ (KCa), ATP-sensitive K+ (KATP), and voltage-gated K+ (KV) channels) and key enzymes (nitric oxide synthase (NOS) and cyclooxygenase (COX)) on nicotine-induced cutaneous vasodilation and sweating. Using intradermal microdialysis, we evaluated forearm cutaneous vascular conductance (CVC) and sweat rate in 2 separate protocols. In protocol 1 (n = 10), 4 separate sites were infused with (i) lactated Ringer (Control), (ii) 50 mmol·L-1 tetraethylammonium (KCa channel blocker), (iii) 5 mmol·L-1 glybenclamide (KATP channel blocker), and (iv) 10 mmol·L-1 4-aminopyridine (KV channel blocker). In protocol 2 (n = 10), 4 sites were infused with (i) lactated Ringer (Control), (ii) 10 mmol·L-1 Nω-nitro-l-arginine (NOS inhibitor), (iii) 10 mmol·L-1 ketorolac (COX inhibitor), or (iv) a combination of NOS+COX inhibitors. At all sites, nicotine was infused in a dose-dependent manner (1.2, 3.6, 11, 33, and 100 mmol·L-1; each for 25 min). Nicotine-induced increase in CVC was attenuated by the KCa, KATP, and KV channel blockers, whereas nicotine-induced increase in sweat rate was reduced by the KCa and KV channel blockers (P ≤ 0.05). COX inhibitor augmented nicotine-induced increase in CVC (P ≤ 0.05), which was absent when NOS inhibitor was co-administered (P > 0.05). In addition, our secondrary experiment (n = 7) demonstrated that muscarinic receptor blockade with 58 μmol·L-1 atropine sulfate salt monohydrate abolished nicotine-induced increases in CVC (1.2-11 mmol·L-1) and sweating (all doses). We show that under a normothermic resting state: (i) KCa, KATP, and KV channels contribute to nicotinic cutaneous vasodilation, (ii) inhibition of COX augments nicotinic cutaneous vasodilation likely through NOS-dependent mechanism(s), and (iii) KCa and KV channels contribute to nicotinic sweating.
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Affiliation(s)
- Naoto Fujii
- a Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada
| | - Jeffrey C Louie
- a Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada
| | - Brendan D McNeely
- a Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada
| | - Tatsuro Amano
- b Laboratory for Exercise and Environmental Physiology, Faculty of Education, Niigata University, Japan
| | - Takeshi Nishiyasu
- c Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba City, Japan
| | - Glen P Kenny
- a Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada
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Dumez JN. Perspectives on hyperpolarised solution-state magnetic resonance in chemistry. Magn Reson Chem 2017; 55:38-46. [PMID: 27495362 DOI: 10.1002/mrc.4496] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 07/28/2016] [Accepted: 08/01/2016] [Indexed: 06/06/2023]
Abstract
This perspective article reviews some of the recent developments in the field of hyperpolarisation, with a focus on solution-state NMR spectroscopy of small molecules. Two techniques are considered in more detail, dissolution dynamic nuclear polarisation (D-DNP) and signal amplification by reversible exchange (SABRE). Some of the opportunities and challenges for applications of hyperpolarised solution-state magnetic resonance in chemistry are discussed. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Jean-Nicolas Dumez
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
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Mewis RE. Developments and advances concerning the hyperpolarisation technique SABRE. Magn Reson Chem 2015; 53:789-800. [PMID: 26264565 DOI: 10.1002/mrc.4280] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 05/08/2015] [Accepted: 05/20/2015] [Indexed: 06/04/2023]
Abstract
To overcome the inherent sensitivity issue in NMR and MRI, hyperpolarisation techniques are used. Signal Amplification By Reversible Exchange (SABRE) is a hyperpolarisation technique that utilises parahydrogen, a molecule that possesses a nuclear singlet state, as the source of polarisation. A metal complex is required to break the singlet order of parahydrogen and, by doing so, facilitates polarisation transfer to analyte molecules ligated to the same complex through the J-coupled network that exists. The increased signal intensities that the analyte molecules possess as a result of this process have led to investigations whereby their potential as MRI contrast agents has been probed and to understand the fundamental processes underpinning the polarisation transfer mechanism. As well as discussing literature relevant to both of these areas, the chemical structure of the complex, the physical constraints of the polarisation transfer process and the successes of implementing SABRE at low and high magnetic fields are discussed.
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Affiliation(s)
- Ryan E Mewis
- School of Science and the Environment, Division of Chemistry and Environmental Science, Manchester Metropolitan University, John Dalton Building, Chester St., Manchester, M1 5GD, UK
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Abstract
17β-Oestradiol (E(2)) is essential for cyclical gonadotrophin-releasing hormone (GnRH) neuronal activity and secretion. In particular, E(2) increases the excitability of GnRH neurones during the afternoon of pro-oestrus in the rodent, which is associated with increased synthesis and secretion of GnRH. It is well established that E(2) regulates the activity of GnRH neurones through both presynaptic and postsynaptic mechanisms. E(2) significantly modulates the mRNA expression of numerous ion channels in GnRH neurones and alters the associated endogenous conductances, including potassium (K(ATP) , A-type) currents and low-voltage T-type and high-voltage L-type calcium currents. Notably, K(ATP) channels are critical for maintaining GnRH neurones in a hyperpolarised state for recruiting the T-type calcium channels, which are important for burst firing in GnRH neurones. In addition, there are other critical channels contributing to burst firing pattern, including the small conductance Ca(2+) -activated K(+) channels that may be modulated by E(2) . Despite these advances, the cellular mechanisms underlying the cyclical GnRH neuronal activity and GnRH release are largely unknown. Ultimately, the ensemble of both pre- and postsynaptic targets of the actions of E(2) will dictate the excitability and activity pattern of GnRH neurones.
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Affiliation(s)
- O K Rønnekleiv
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR 97239-3098, USA.
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14
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Gendron ME, Thorin E, Perrault LP. Loss of endothelial KATP channel-dependent, NO-mediated dilation of endocardial resistance coronary arteries in pigs with left ventricular hypertrophy. Br J Pharmacol 2004; 143:285-91. [PMID: 15326036 PMCID: PMC1575339 DOI: 10.1038/sj.bjp.0705937] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2004] [Revised: 06/29/2004] [Accepted: 07/08/2004] [Indexed: 11/08/2022] Open
Abstract
The influence of left ventricular hypertrophy (LVH) on the endothelial function of resistance endocardial arteries is not well established. The aim of this study was to characterise the mechanisms responsible for UK-14,304 (alpha(2)-adrenoreceptor agonist)-induced endothelium-dependent dilation in pig endocardial arteries isolated from hearts with or without LVH. LVH was induced by aortic banding 2 months before determining endothelial function. Following euthanasia, hearts were harvested and endocardial resistance arteries were isolated and pressurised to 100 mmHg in no-flow conditions. Vessels were preconstricted with acetylcholine (ACh) or high external K(+) (40 mmol l(-1) KCl). Results are expressed as mean+/-s.e.m. UK-14,304 induced a maximal dilation representing 79+/-6% (n=8) of the maximal diameter. NO synthase (l-NNA, 10 micromol l(-1), n=7) or guanylate cyclase (ODQ, 10 micromol l(-1), n=4) inhibition reduced (P<0.05) UK-14,304-dependent dilation to 35+/-6 and 18+/-7%, respectively. Apamin and charybdotoxin reduced (P<0.05) to 39+/-8% (n=4) the dilation induced by UK-14,304. In depolarised conditions, however, this dilation was prevented (P<0.05). UK-14,304-induced dilation was reduced (P<0.05) by glibenclamide (Glib, 1 micromol l(-1)), a K(ATP) channel blocker, either alone (35+/-10%, n=5) or in combination with l-NNA (34+/-9%, n=4). In LVH, UK-14,304-induced maximal dilation was markedly reduced (25+/-4%, P<0.05) compared to control; it was insensitive to l-NNA (21+/-5%) but prevented either by the combination of l-NNA, apamin and charybdotoxin, or by 40 mmol l(-1) KCl. Activation of endothelial alpha(2)-adrenoreceptor induces an endothelium-dependent dilation of pig endocardial resistance arteries. This dilation is in part dependent on NO, the release of which appears to be dependent on the activation of endothelial K(ATP) channels. This mechanism is blunted in LVH, leading to a profound reduction in UK-14,304-dependent dilation.
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Affiliation(s)
- Marie-Eve Gendron
- Department of Surgery and Research Center, Institut de Cardiologie de Montréal, 5000, rue Bélanger, Montréal, Québec, Canada H1T 1C8
- Department of Pharmacology, Université de Montréal, Canada
| | - Eric Thorin
- Department of Surgery and Research Center, Institut de Cardiologie de Montréal, 5000, rue Bélanger, Montréal, Québec, Canada H1T 1C8
| | - Louis P Perrault
- Department of Surgery and Research Center, Institut de Cardiologie de Montréal, 5000, rue Bélanger, Montréal, Québec, Canada H1T 1C8
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15
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Imaeda K, Trout SJ, Cunnane TC. Mechanical and electrophysiological effects of endothelin-1 on guinea-pig isolated lower oesophageal sphincter circular smooth muscle. Br J Pharmacol 2002; 135:197-205. [PMID: 11786495 PMCID: PMC1573100 DOI: 10.1038/sj.bjp.0704426] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2001] [Revised: 09/19/2001] [Accepted: 10/02/2001] [Indexed: 11/09/2022] Open
Abstract
1. The effects of endothelin-1 (ET-1) on guinea-pig lower oesophageal sphincter (LOS) circular smooth muscle were investigated by using intracellular microelectrodes and isometric tension recording techniques. 2. ET-1 produced biphasic mechanical responses; an initial transient relaxation followed by a sustained contraction. The initial relaxation was not inhibited by either tetrodotoxin (TTX, 1 microM) or L-N(G)-nitroarginine (L-NOARG, 100 microM). The sustained contraction was greatly attenuated by nifedipine (1 microM). 3. ET-1 (1 - 30 nM) induced a concentration-dependent hyperpolarisation that was unaffected by TTX or L-NOARG. The ET(A) receptor antagonist, BQ123 (0.3 microM) abolished the ET-1-induced hyperpolarisation, whereas the ET(B) receptor antagonist, BQ788 (0.3 microM) had no detectable effect. Sarafotoxin S6c (10 nM) did not change the membrane potential. 4. The ET-1-induced hyperpolarisation was abolished by apamin (0.1 microM). Interestingly, apamin abolished the ET-1-induced transient relaxation but potentiated the sustained contraction. 5. In Ca(2+)-free Krebs solution, the ET-1-induced hyperpolarisation was greatly attenuated and returned to the control value when the tissue was reperfused with Krebs solution containing Ca(2+). The ET-1-induced hyperpolarisation was insensitive to nifedipine but was attenuated by SK&F 96365 (1 - [beta-[3-(4 - methoxy - phenyl)propoxy] - 4 - methoxyphenethyl] - 1H-imidazole hydrochloride, 50 microM), an inhibitor of receptor-mediated Ca(2+) entry. The residual component of the ET-1-induced hyperpolarisation was sensitive to thapsigargin (1 microM). 6. These results demonstrate that, in guinea-pig LOS circular smooth muscle, ET-1 hyperpolarizes the membrane by activating apamin-sensitive K(+) channels, mainly as a result of receptor-mediated Ca(2+) entry and partly by Ca(2+) release from intracellular stores. The hyperpolarisation triggers the initial transient relaxation, which acts to oppose the sustained contraction.
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Affiliation(s)
- Kenro Imaeda
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Stephen J Trout
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Thomas C Cunnane
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT
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